The amount of people suffering from different musculo-skeletal complaints, such as back pain or knee problems, is large. As a consequence, orthopaedic physicians and physiotherapists are required to analyse a variety of movements of the body to diagnose pathological or abnormal changes. Up to now, time-dependent three-dimensional recordings of movement under functional conditions are not possible with conventional techniques. As an ersatz, one or more three-dimensional scans (e.g. RX) of selected body parts, such as e.g. knees or feet, are made under given conditions, such as e.g. bending of the limbs/extension, i.e. stretching, of the limbs, or video-based kinematographic methods, such as e.g. marker tracing are used to calculate kinematical parameters, i.e. for example for gait analysis. An overview of the history and technical constraints and different available systems is given by D. H. Sutherland in “The evolution of clinical gait analysis. Part II Kinematics”, Gait and Posture (2002), 16, 159-179.
US Patent application US 2002/0009222 A1 describes a method for determining kinetic and kinematic information for a 3D image of a human body. It is based on an input device for images, a transformation system to obtain 3D information and a system for obtaining kinematic and kinetic information. The image input is based on information of markers placed on the object. This information is transformed into a 3D image based on an anatomical coordinate system of the body segment. Finally the positions and orientations are computed in global space for dynamical images. US 2002/0009222 does not provide a non-contact technique for obtaining information and furthermore does not use muscular modelling. The application of landmark markers to the body is time consuming and must be tolerated by patients.
U.S. Pat. No. 6,169,817 B1 describes a system and method for 4D kinematic reconstruction and visualization of body tissue. The method is based on segmenting a 3D image, following the motion of the different segments, e.g. based on finite element models and using the detailed four-dimensional representation of bone, muscles, skin and other tissue as a digital clone to study the motion and biomechanical properties. The document describes the construction of a model based on expensive techniques and involving potentially harmful techniques which require careful management.
In “4D analysis of muscular dynamics using flexible 3D muscle models”, International Conference on Artificial Reality and Telexistence '99, Suziki et al. describe a method for constructing a 4D musculo-skeletal model. The method is based on fitting a muscular and skeletal model to MRI results and measuring movement by a video camera and a set of sensors.
The above-mentioned documents describe the construction of a biomechanical model based on expensive techniques and potentially harmful medical techniques which require careful control to maintain proper patient care. Furthermore, the methods described in the above mentioned documents have the disadvantage that the computing power needed for time-dependent detection of landmarks on time-dependent images of body parts can be high. The above mentioned documents furthermore have the disadvantage that a musculo-skeletal model only can be obtained based on images of the interior of the body parts. Furthermore, the above mentioned documents have the disadvantage that the musculo-skeletal model obtained can lead to bio-mechanical inconsistent features and that the computing power for obtaining the musculo-skeletal model is large. Due to the large computing power needed, the systems and methods for obtaining a musculo-skeletal model are tedious and labour-intensive.